Synthesis, characterisation and corrosion behaviour of simulant Chernobyl nuclear meltdown materials

Understanding the physical and chemical properties of materials arising from nuclear meltdowns, such as the Chernobyl and Fukushima accidents, is critical to supporting decommissioning operations and reducing the hazard to personnel and the environment surrounding the stricken reactors. Relatively few samples of meltdown materials are available for study, and their analysis is made challenging due to the radiation hazard associated with handling them. In this study, small-scale batches of low radioactivity (i.e., containing depleted uranium only) simulants for Chernobyl lava-like fuel-containing materials (LFCMs) have been prepared, and were found to closely approximate the microstructure and mineralogy of real LFCM. The addition of excess of ZrO2 to the composition resulted in the first successful synthesis of high uranium–zircon (chernobylite) by crystallisation from a glass melt. Use of these simulant materials allowed further analysis of the thermal characteristics of LFCM and the corrosion kinetics, giving results that are in good agreement with the limited available literature on real samples. It should, therefore, be possible to use these new simulant materials to support decommissioning operations of nuclear reactors post-accident.